1. Field of the Invention
The present invention relates to a focus adjusting apparatus, a camera including the focus adjusting apparatus, and a method for adjusting focus of an optical system.
2. Description of the Related Art
Conventionally, in electronic cameras such as digital still cameras, so-called hill-climbing contrast detection AF is known that performs AF using a focus evaluation value obtained based on a high-frequency component of an image imaged by an imaging device. In such cameras, at the time of moving-image shooting where focus adjustment is always performed on a subject or at the time of a continuous AF operation, when the focus evaluation value is changed by a predetermined amount, it is determined that the state of the subject in an AF area has been changed and thus an AF operation restarts (refer to, for example, Japanese Patent Application Laid-Open No. 2003-121721). The contents of Japanese Patent Application Laid-Open No. 2003-121721 are incorporated herein by reference in their entirety.